Thanks for the clear details and information provided.
So you originally performed an AUTOINSTALL to successfully upgrade to 3.4.21194 and then a downgrade (thus reformat) to go to 3.4.22048 with maps which produced the black screen after the reboot.
As said on discord, that APIM does not seem to be MY20 based on the manufacture date and being a J series APIM.
BUT (and this is a sad but) we had some reports of users with your exact same issue.
For instance in Black Screen after update from Sync 3 v3.0 to v3.3 - Ford Mustang 2018 a user had this issue with a J series APIM.
This is what you could try to see if it helps, no guarantee since the black screen was produced after a reformat, but it’s worth trying:
Reformat Boot Screen Recovery.pdf (113,9 KB)
reformat.lst (44 Bytes)
Also, let me call for @F150Chief for additional help.
What do you think about this?.